Catheter ablation for ventricular tachycardia following surgical treatment of pulmonary stenosis with intact ventricular septum

This study was aimed to report the characteristics and treatment of ventricular tachycardia (VT) following surgical treatment of pulmonary stenosis with intact ventricular septum.

Five patients underwent radiofrequency catheter ablation for sustained monomorphic left bundle branch block (LBBB) type VT who previously underwent surgical treatment of pulmonary stenosis. Except stimulation, voltage and activation mapping was performed using three-dimensional (3D) electro-anatomic mapping and ablation was applied accordingly. Four VTs were induced during EP study. Two VTs were focal and the earliest activity was targeted in the right ventricular apex (RVA). The other two VTs were reentrant and the critical isthmus located in the mid-lateral wall and anterior wall of right ventricle, respectively. Ablation abolished all inducible VTs in four patients. In the patient whose VT was non-inducible, radiofrequency (RF) energy was delivered to the RVA where pacing mapping matched the clinical VT. One focal VT recurred 60 months after the initial RF ablation. Repeat mapping and ablation was performed and no VT recurred over a 24-month period.

The mechanism of VT following surgical treatment of pulmonary stenosis can be either focal or reentrant. Ablation of this subgroup of VT is feasible.